The Vivitrol shot is a once-monthly injection of extended-release naltrexone, FDA-approved to treat both opioid use disorder and alcohol use disorder. Its biggest appeal is simple: 1 shot a month instead of remembering a daily pill, which removes the adherence challenge that trips up many people in recovery. It works by blocking opioid receptors, so opioids can't produce a high and, for alcohol, the reward and craving are reduced. But Vivitrol comes with one critical requirement that makes timing essential — you must be fully off opioids before starting it — and some important trade-offs to understand.
This guide explains how the Vivitrol shot works, who it's for, the detox requirement, and the pros and cons versus other options. Updated April 2026. Reviewed by the RehabPulse editorial team. This is educational and not medical advice.
The 60-second answer
| Question | Short answer |
|---|---|
| What is Vivitrol? | A once-monthly injection of extended-release naltrexone |
| What does it treat? | Opioid use disorder and alcohol use disorder |
| How does it work? | Blocks opioid receptors; reduces reward and craving |
| Main advantage? | Monthly dosing — no daily pill to remember |
| The key requirement? | Must be fully off opioids first (about 7–10 days) |
| Is it addictive? | No — naltrexone isn't a controlled substance or opioid |
| Big caution? | Overdose risk rises if someone relapses after stopping |
| How does it compare? | Different approach than buprenorphine/methadone |
The single most important point: most people don't know that you have to be completely off opioids — usually for about 7 to 10 days — before getting the Vivitrol shot, or it can trigger sudden, severe "precipitated" withdrawal. This detox requirement is the biggest practical hurdle and the main difference from medications like buprenorphine. Getting the timing right is essential, which is why Vivitrol for opioids is started under medical guidance after detox, not while someone is still using.
What Vivitrol is and how it works
Vivitrol is the brand name for extended-release injectable naltrexone — the same medication as oral naltrexone, but formulated to release slowly over about a month from a single injection given by a healthcare provider (usually in the buttock muscle).
Naltrexone is an opioid antagonist: it binds to and blocks opioid receptors. This has two effects depending on what's being treated:
- For opioid use disorder: With the receptors blocked, opioids can't attach and produce a high. This removes the reward from using opioids, which helps prevent relapse — if someone uses, they won't feel the effect.
- For alcohol use disorder: Because alcohol's pleasurable effects partly involve the opioid system, blocking those receptors reduces alcohol's reward and cravings (the same mechanism as in our naltrexone for alcohol guide).
The defining feature is the monthly dosing. Instead of taking a pill every day — and potentially forgetting, or choosing not to, during a craving — a person gets one shot that provides steady protection for about a month. For many people, this consistency is a major advantage. It's one of the medications covered in our medication-assisted treatment guide and medications for alcohol use disorder guide.
Picture this: someone in recovery from opioid use disorder who genuinely wants to stay clean but knows that in a moment of intense craving, a daily pill is easy to "forget" to take. With Vivitrol, that decision is already made for the whole month — the protection is in their system regardless of any single bad moment. For a person whose main vulnerability is daily adherence, that monthly commitment can be the structure that holds their recovery together. That's the core value of the shot.
Who Vivitrol is for and the detox requirement
Vivitrol can be a good fit for specific situations:
- People who struggle with daily pills. The monthly shot removes the adherence challenge, which is its main strength.
- People committed to an opioid-free approach. Unlike buprenorphine or methadone (which are opioids that prevent withdrawal and cravings), Vivitrol is non-opioid — it doesn't replace one opioid with another, which appeals to some people and some programs.
- Alcohol use disorder. It's an effective option for AUD, especially for those who want monthly dosing.
- Certain settings. It's often used in criminal-justice and reentry programs, and after detox or residential treatment.
The critical requirement, especially for opioids, is the detox prerequisite:
- You must be fully off opioids first — typically about 7 to 10 days — before the first Vivitrol shot. Because naltrexone blocks and displaces opioids from receptors, taking it while opioids are still in the system can cause sudden, severe precipitated withdrawal, which is intensely unpleasant.
- This is the main hurdle. Getting through detox before starting is the biggest barrier to Vivitrol for opioid use disorder, and it's why it's started under medical supervision. (For alcohol, this opioid-free requirement still applies to anyone using opioids, but there's no need to be alcohol-free to start.)
Our how long does opioid withdrawal last guide explains the detox period that must precede the shot.
The pros and cons
Vivitrol has clear advantages and real limitations, and it's important to weigh both:
| Pros | Cons |
|---|---|
| Monthly dosing — no daily pill | Detox required first (precipitated-withdrawal risk) |
| Non-opioid, non-addictive | Overdose risk after stopping (lowered tolerance) |
| Removes adherence struggle | Can't be used with opioid pain meds |
| No abuse/diversion potential | Doesn't ease withdrawal like buprenorphine does |
| Works for opioids and alcohol | Side effects (injection-site reactions, nausea) |
The most important caution to understand:
- Overdose risk after stopping. Because Vivitrol blocks opioids and reduces tolerance, if someone stops the shot and then relapses on opioids, their lowered tolerance means a previously normal dose could cause a fatal overdose. This is a serious risk to be aware of, and a reason continuity of care matters.
- It doesn't relieve withdrawal or cravings the way opioids-based medications do. Buprenorphine and methadone actively prevent withdrawal and cravings by acting on opioid receptors; naltrexone just blocks them, so it doesn't help someone get through withdrawal — that's why detox must happen first. Some people find this harder to start and stay on.
- Comparison matters. For opioid use disorder, research generally shows buprenorphine and methadone have strong evidence (and don't require detox first); Vivitrol is also effective once started, but the detox hurdle means more people drop out before the first shot. The "best" medication depends on the person — our suboxone vs methadone guide covers the opioid-agonist options.
Imagine two people starting opioid treatment. One does well on buprenorphine, which eases their withdrawal and cravings from day one without needing to fully detox first. The other strongly prefers a non-opioid approach and, after completing detox in a supervised program, does well on monthly Vivitrol because it fits their values and removes daily-pill stress. Both are valid, evidence-based paths — the right one depends on the person's situation, preferences, and ability to get through detox. This is a decision to make with a knowledgeable provider.
Getting started and what to expect
If Vivitrol might be right for you or a loved one:
- Talk to a provider. A doctor will assess whether Vivitrol fits your situation, goals, and (for opioids) readiness, and will plan the necessary detox.
- Complete detox first (for opioids). You'll need to be opioid-free for the required period; this is done with medical support to manage withdrawal safely.
- Get the monthly injection. A provider administers the shot roughly every four weeks; consistency month to month is key to protection.
- Combine with support. Like all medications for addiction, Vivitrol works best alongside counseling, therapy, and support — it's a powerful tool, not a standalone cure.
- Plan for continuity. Because of the post-stopping overdose risk, have a plan for ongoing treatment rather than abrupt discontinuation, and discuss any changes with your provider.
The encouraging bottom line: Vivitrol is an effective, non-addictive, once-monthly option for both opioid and alcohol use disorder that solves the daily-adherence problem for many people. The SAMHSA national helpline (1-800-662-HELP) is free, confidential, and available 24/7 for treatment referrals. Other resources on RehabPulse:
Frequently asked questions
What is the Vivitrol shot? The Vivitrol shot is a once-monthly injection of extended-release naltrexone, FDA-approved to treat both opioid use disorder and alcohol use disorder. It's the same medication as oral naltrexone but released slowly over about a month from a single injection given by a healthcare provider. Naltrexone is an opioid antagonist that blocks opioid receptors, so opioids can't produce a high and, for alcohol, the reward and cravings are reduced. Its main appeal is monthly dosing instead of a daily pill.
How does Vivitrol work for opioids and alcohol? Vivitrol works by blocking the brain's opioid receptors. For opioid use disorder, this means opioids can't attach and produce a high, removing the reward from using and helping prevent relapse. For alcohol use disorder, because alcohol's pleasurable effects partly involve the opioid system, blocking those receptors reduces alcohol's reward and cravings. In both cases it provides steady receptor blockade for about a month from a single injection, without being an opioid itself.
Why do you have to detox before getting Vivitrol? Because naltrexone blocks and displaces opioids from their receptors, taking it while opioids are still in your system can trigger sudden, severe "precipitated" withdrawal — an intensely unpleasant reaction. To avoid this, you must be fully off opioids first, typically for about 7 to 10 days, before the first shot. This detox requirement is the biggest practical hurdle for Vivitrol in opioid use disorder and is why it's started under medical supervision after detox rather than while someone is still using.
Is Vivitrol addictive? No. Naltrexone (the medication in Vivitrol) is not an opioid and not a controlled substance — it has no abuse potential and doesn't produce a high or dependence. This is different from buprenorphine and methadone, which are opioids (used safely in treatment, but with their own considerations). Because Vivitrol is non-opioid and non-addictive, it appeals to people and programs that prefer an approach that doesn't involve any opioid medication.
What are the risks or downsides of Vivitrol? The main ones: you must complete detox before starting (with precipitated-withdrawal risk if you don't), and there's a serious overdose risk if someone stops the shot and then relapses on opioids, because their lowered tolerance makes a previously normal dose potentially fatal. Vivitrol also doesn't relieve withdrawal or cravings the way buprenorphine and methadone do (it only blocks receptors), can't be used with opioid pain medications, and has side effects like injection-site reactions and nausea. The right medication depends on the individual and should be chosen with a provider.
Sources and references
- Substance Abuse and Mental Health Services Administration (SAMHSA). Naltrexone. samhsa.gov
- U.S. Food and Drug Administration (FDA). Vivitrol (naltrexone for extended-release injectable suspension). fda.gov
- National Institute on Drug Abuse (NIDA). Medications to Treat Opioid Use Disorder. nida.nih.gov
- National Library of Medicine (MedlinePlus). Naltrexone Injection. medlineplus.gov
- Substance Abuse and Mental Health Services Administration (SAMHSA). National Helpline — 1-800-662-HELP (4357), free and confidential 24/7. samhsa.gov/find-help/national-helpline
- National Institute on Alcohol Abuse and Alcoholism (NIAAA). Medications for Alcohol Use Disorder. niaaa.nih.gov
- SAMHSA. FindTreatment.gov treatment locator. findtreatment.gov
